lung defence

Question 1

defence mechanisms of the respiratory tract

Answer 1

filtration and deposition in upper airways
cough reflex
mucocilliary clearance
innate and adaptive immune response

Question 2

primary ciliary disease (kartagener’s syndrome)

Answer 2

rare, inherited disorder leads to impaired ciliary function, progressive sino-pulmonary disease
50% have situs inversus totalis

Question 3

what are immunoglobulins

Answer 3

glycoproteins found in serum and tissue fluid
produced in response to contact with immunogenicity foreign molecules
produced by plasma cells
bind specifically to the antigen that induced their info

Question 4

immunoglobulin distribution

Answer 4

IgM: circulation
IgG: circulation and most tissues
IgA: skin mucosal membranes as a dimer; monomer when in circulation
IgE: mucosal membranes: gut, airway and skin

Question 5

IgG

Answer 5

monomer structure, four subclasses
main Ab in serum and tissue fluids - 75% of total serum immunoglobulin
extra vascular
fixes complement
opsonisation

Question 6

IgA

Answer 6

predominant Ab found in secretions
dimer or trimer structure
important in mucosal immunity
present on mucosal membranes
good neutralising Ab

Question 7

IgE

Answer 7

monomer
normally very low serum levels
likely specifically developed against parasite infections
important in allergy

Question 8

IgM

Answer 8

predominant Ab in primary immune response
10% of total serum Ig
pentameter structure in serum
found on B cell surface as monomer
neutralises and opsonises antigens

Question 9

what are macrophages derived from

Answer 9

circulating monocytes (live 2-3 days)
when in tissue they morph into macrophages (live 60-120 days)

Question 10

what do scavenger cells do

Answer 10

dispose of dead cells, cell debris, particulate matter and invading microorganisms via phagocytosis

Question 11

what do sentinel cells do

Answer 11

sense pathogens and release cytokines —> neutrophil recruitment from blood

Question 12

stages of phagocytosis

Answer 12

1. bacterium attaches to membrane
2. bacterium is ingested, forming phagosomr
3. phagosome fuses with lysosome
4. lysozymes digest the bacteria
5. digested material released from cell - exocytosis

Question 13

what types of cells are classed as phagocytes

Answer 13

macrophage
neutrophils
dendritic cells

Question 14

innate immune responses in early lungs

Answer 14

airway epithelial cells
NK cells
dendritic cells
innate lymphoid cells (type II)
neutrophils
alveolar macrophages

Question 15

respiratory syncytial virus (RSV) bronchitis

Answer 15

causes a lot of disease in young babies
60% have <1 year mild upper resp tract infection
40% have upper and lower RTI (bronchiolitis)